Late blight caused by Phytophthora infestans is historically a serious epidemic disease in potato and tomato cultivations. Accession L3708 (Solanum pimpinellifolium), a new source for late blight resistance was identified in AVRDC, and carries the resistance gene, Ph-3, incompatible to P. infestans race 3. The AFLP markers linked to Ph-3 were previously developed from the L3708 accession (Chunwongse et al. 2002). To facilitate tomato breeding with the Ph-3 gene, an attempt was made to convert AFLP markers to sequence-characterized amplified region (SCAR) markers. Among 6 AFLP markers, only one AFLP marker, L87, was successfully converted to SCAR marker. The resistance-specific 230 bp AFLP fragment was cloned and sequenced, and the PCR primer amplifying a 123 bp fragment was designed. This SCAR marker could discriminate resistant and susceptible individuals with high stringency. The developed SCAR marker could be used for the marker assisted-selection in tomato breeding programs.